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Article

Koraljka Golub, Marianne Lykke and Douglas Tudhope

The purpose of this paper is to explore the potential of applying the Dewey Decimal Classification (DDC) as an established knowledge organization system (KOS) for…

Abstract

Purpose

The purpose of this paper is to explore the potential of applying the Dewey Decimal Classification (DDC) as an established knowledge organization system (KOS) for enhancing social tagging, with the ultimate purpose of improving subject indexing and information retrieval.

Design/methodology/approach

Over 11,000 Intute metadata records in politics were used. Totally, 28 politics students were each given four tasks, in which a total of 60 resources were tagged in two different configurations, one with uncontrolled social tags only and another with uncontrolled social tags as well as suggestions from a controlled vocabulary. The controlled vocabulary was DDC comprising also mappings from the Library of Congress Subject Headings.

Findings

The results demonstrate the importance of controlled vocabulary suggestions for indexing and retrieval: to help produce ideas of which tags to use, to make it easier to find focus for the tagging, to ensure consistency and to increase the number of access points in retrieval. The value and usefulness of the suggestions proved to be dependent on the quality of the suggestions, both as to conceptual relevance to the user and as to appropriateness of the terminology.

Originality/value

No research has investigated the enhancement of social tagging with suggestions from the DDC, an established KOS, in a user trial, comparing social tagging only and social tagging enhanced with the suggestions. This paper is a final reflection on all aspects of the study.

Details

Journal of Documentation, vol. 70 no. 5
Type: Research Article
ISSN: 0022-0418

Keywords

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Article

Michael John Khoo, Jae-wook Ahn, Ceri Binding, Hilary Jane Jones, Xia Lin, Diana Massam and Douglas Tudhope

– The purpose of this paper is to describe a new approach to a well-known problem for digital libraries, how to search across multiple unrelated libraries with a single query.

Abstract

Purpose

The purpose of this paper is to describe a new approach to a well-known problem for digital libraries, how to search across multiple unrelated libraries with a single query.

Design/methodology/approach

The approach involves creating new Dewey Decimal Classification terms and numbers from existing Dublin Core records. In total, 263,550 records were harvested from three digital libraries. Weighted key terms were extracted from the title, description and subject fields of each record. Ranked DDC classes were automatically generated from these key terms by considering DDC hierarchies via a series of filtering and aggregation stages. A mean reciprocal ranking evaluation compared a sample of 49 generated classes against DDC classes created by a trained librarian for the same records.

Findings

The best results combined weighted key terms from the title, description and subject fields. Performance declines with increased specificity of DDC level. The results compare favorably with similar studies.

Research limitations/implications

The metadata harvest required manual intervention and the evaluation was resource intensive. Future research will look at evaluation methodologies that take account of issues of consistency and ecological validity.

Practical implications

The method does not require training data and is easily scalable. The pipeline can be customized for individual use cases, for example, recall or precision enhancing.

Social implications

The approach can provide centralized access to information from multiple domains currently provided by individual digital libraries.

Originality/value

The approach addresses metadata normalization in the context of web resources. The automatic classification approach accounts for matches within hierarchies, aggregating lower level matches to broader parents and thus approximates the practices of a human cataloger.

Details

Journal of Documentation, vol. 71 no. 5
Type: Research Article
ISSN: 0022-0418

Keywords

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Article

Hiren K. Mewada and Jitendra Chaudhari

The digital down converter (DDC) is a principal component in modern communication systems. The DDC process traditionally entails quadrature down conversion, bandwidth…

Abstract

Purpose

The digital down converter (DDC) is a principal component in modern communication systems. The DDC process traditionally entails quadrature down conversion, bandwidth reducing filters and commensurate sample rate reduction. To avoid group delay, distortion linear phase FIR filters are used in the DDC. The filter performance specifications related to deep stopband attenuation, small in-band ripple and narrow transition bandwidth lead to filters with a large number of coefficients. To reduce the computational workload of the filtering process, filtering is often performed as a two-stage process, the first stage being a down sampling Hoegenauer (or cascade-integrated comb) filter and a reduced sample rate FIR filter. An alternative option is an M-Path polyphase partition of a band cantered FIR filter. Even though IIR filters offer reduced workload to implement a specific filtering task, the authors avoid using them because of their poor group delay characteristics. This paper aims to propose the design of M-path, approximately linear phase IIR filters as an alternative option to the M-path FIR filter.

Design/methodology/approach

Two filter designs are presented in the paper. The first approach uses linear phase IIR low pass structure to reduce the filter’s coefficient. Whereas the second approach uses multipath polyphase structure to design approximately linear phase IIR filter in DDC.

Findings

The authors have compared the performance and workload of the proposed polyphase structured IIR filters with state-of-the-art filter design used in DDC. The proposed design is seen to satisfy tight design specification with a significant reduction in arithmetic operations and required power consumption.

Originality/value

The proposed design is an alternate solution to the M-path polyphase FIR filter offering very less number of coefficients in the filter design. Proposed DDC using polyphase structured IIR filter satisfies the requirement of linear phase with the least number of computation cost in comparison with other DDC structure.

Details

Circuit World, vol. 45 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

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Article

Haroon Idrees

The purpose of this paper is to develop understanding of the problems of classification, to discover the classification practices of libraries with rich collections on…

Abstract

Purpose

The purpose of this paper is to develop understanding of the problems of classification, to discover the classification practices of libraries with rich collections on Islam cited in the literature, to find the gaps, and to determine the point from which to start work on further development.

Design/methodology/approach

Published and unpublished literature, both print and electronic, that is relevant to the problem was reviewed objectively in the compilation of this paper.

Findings

Standard classification systems lack proper space for materials on Islam for two reasons: less awareness on the part of devisers of the depth and variety of Islamic topics; and their bias and lack of interest in Islam. Different indigenous classification systems and expansions have been developed, using either the original notation or alternative notations. Some systems have been developed without following any standards or logic. This study has revealed a need for empirical study of libraries with rich collections on Islam in order to gain a better understanding of the problem and find an optimal solution.

Research limitations/implications

No empirical field data are included in this study. This is a review of the literature.

Originality/value

The author indicates the current situation of the problem and a potential framework for its solution.

Details

OCLC Systems & Services: International digital library perspectives, vol. 27 no. 2
Type: Research Article
ISSN: 1065-075X

Keywords

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Article

Hamid Saeed and Abdus Sattar Chaudhry

Terms drawn from DDC indexes and IEEE Web Thesaurus were merged with DDC hierarchies to build a taxonomy in the domain of computer science. When displayed as a directory…

Abstract

Terms drawn from DDC indexes and IEEE Web Thesaurus were merged with DDC hierarchies to build a taxonomy in the domain of computer science. When displayed as a directory structure using a shareware tool MyInfo, the resultant taxonomy appeared to be a promising tool for categorisation that can facilitate browsing of information resources in an electronic environment.

Details

Journal of Documentation, vol. 58 no. 5
Type: Research Article
ISSN: 0022-0418

Keywords

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Article

Arash Joorabchi and Abdulhussain E. Mahdi

This paper aims to report on the design and development of a new approach for automatic classification and subject indexing of research documents in scientific digital…

Abstract

Purpose

This paper aims to report on the design and development of a new approach for automatic classification and subject indexing of research documents in scientific digital libraries and repositories (DLR) according to library controlled vocabularies such as DDC and FAST.

Design/methodology/approach

The proposed concept matching-based approach (CMA) detects key Wikipedia concepts occurring in a document and searches the OPACs of conventional libraries via querying the WorldCat database to retrieve a set of MARC records which share one or more of the detected key concepts. Then the semantic similarity of each retrieved MARC record to the document is measured and, using an inference algorithm, the DDC classes and FAST subjects of those MARC records which have the highest similarity to the document are assigned to it.

Findings

The performance of the proposed method in terms of the accuracy of the DDC classes and FAST subjects automatically assigned to a set of research documents is evaluated using standard information retrieval measures of precision, recall, and F1. The authors demonstrate the superiority of the proposed approach in terms of accuracy performance in comparison to a similar system currently deployed in a large scale scientific search engine.

Originality/value

The proposed approach enables the development of a new type of subject classification system for DLR, and addresses some of the problems similar systems suffer from, such as the problem of imbalanced training data encountered by machine learning-based systems, and the problem of word-sense ambiguity encountered by string matching-based systems.

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Article

Alexander Mehler and Ulli Waltinger

The purpose of this paper is to present a topic classification model using the Dewey Decimal Classification (DDC) as the target scheme. This is to be done by exploring…

Abstract

Purpose

The purpose of this paper is to present a topic classification model using the Dewey Decimal Classification (DDC) as the target scheme. This is to be done by exploring metadata as provided by the Open Archives Initiative (OAI) to derive document snippets as minimal document representations. The reason is to reduce the effort of document processing in digital libraries. Further, the paper seeks to perform feature selection and extension by means of social ontologies and related web‐based lexical resources. This is done to provide reliable topic‐related classifications while circumventing the problem of data sparseness. Finally, the paper aims to evaluate the model by means of two language‐specific corpora. The paper bridges digital libraries, on the one hand, and computational linguistics, on the other. The aim is to make accessible computational linguistic methods to provide thematic classifications in digital libraries based on closed topic models such as the DDC.

Design/methodology/approach

The approach takes the form of text classification, text‐technology, computational linguistics, computational semantics, and social semantics.

Findings

It is shown that SVM‐based classifiers perform best by exploring certain selections of OAI document metadata.

Research limitations/implications

The findings show that it is necessary to further develop SVM‐based DDC‐classifiers by using larger training sets possibly for more than two languages in order to get better F‐measure values.

Originality/value

Algorithmic and formal‐mathematical information is provided on how to build DDC‐classifiers for digital libraries.

Details

Library Hi Tech, vol. 27 no. 4
Type: Research Article
ISSN: 0737-8831

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Article

Maggie Liu

The purpose of this paper is to ensure the provision of effective library support to the scholarly community in areas of collection development and management. Last year…

Abstract

Purpose

The purpose of this paper is to ensure the provision of effective library support to the scholarly community in areas of collection development and management. Last year, the author’s library made the first attempt to conduct a collection evaluation on a multidisciplinary subject – social work.

Design/methodology/approach

In view of extensive subject coverage of a cross-disciplinary subject and the library’s constraints, a cost-effective and manageable strategy using internal resources was used. The focus of the study was to concentrate on core subject areas of social work. By making use of circulation statistics of those areas, adequacy, strengths and weaknesses of the collection would be identified.

Findings

A positive adequacy of the social work collection was evidenced from a high usage of the collection. An in-depth study on the two major active sections, DDC 361 (social problems and services) and DDC 362 (social work for different groups of people), was also undertaken. Specific subject areas for improvement were identified.

Originality/value

Through conducting the project, it not only directly served the main purpose of enhancing the quality of the collection in alliance with the development of academic departments, but also expanded our subject knowledge. It is hoped that our experience can offer tips and stimulant for other libraries contemplating collection analysis on a multidisciplinary subject under restricted resources.

Details

Collection Building, vol. 34 no. 2
Type: Research Article
ISSN: 0160-4953

Keywords

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Book part

Victor Aguirregabiria and Arvind Magesan

We derive marginal conditions of optimality (i.e., Euler equations) for a general class of Dynamic Discrete Choice (DDC) structural models. These conditions can be used to…

Abstract

We derive marginal conditions of optimality (i.e., Euler equations) for a general class of Dynamic Discrete Choice (DDC) structural models. These conditions can be used to estimate structural parameters in these models without having to solve for approximate value functions. This result extends to discrete choice models the GMM-Euler equation approach proposed by Hansen and Singleton (1982) for the estimation of dynamic continuous decision models. We first show that DDC models can be represented as models of continuous choice where the decision variable is a vector of choice probabilities. We then prove that the marginal conditions of optimality and the envelope conditions required to construct Euler equations are also satisfied in DDC models. The GMM estimation of these Euler equations avoids the curse of dimensionality associated to the computation of value functions and the explicit integration over the space of state variables. We present an empirical application and compare estimates using the GMM-Euler equations method with those from maximum likelihood and two-step methods.

Details

Structural Econometric Models
Type: Book
ISBN: 978-1-78350-052-9

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Article

Hwy‐Chang Moon and Min‐Young Kim

The main purpose of this paper is to introduce a comprehensive model explaining the global expansion of firms and to find out viable strategies for firms to survive global…

Abstract

Purpose

The main purpose of this paper is to introduce a comprehensive model explaining the global expansion of firms and to find out viable strategies for firms to survive global competition.

Design/methodology/approach

Through the critical review over existing literature, this study first introduces a new framework explaining the global expansion of firms at the level of functional activities in the value chain, and then empirically tests the predictions of the new framework with data in the motor industry.

Findings

Empirical findings confirm the new model's predictions. First, each function in the value chain has a unique way of global expansion: the global strategy is suitable for the production function, while the multidomestic strategy is applicable to the marketing function. Second, each function follows a dynamic path of global expansion from domestic to transnational via either global or multidomestic, according to the innate characteristics of corresponding function. Finally, the degree of global expansion of a firm is positively correlated with its financial performance.

Research limitations/implications

Focusing on developing a new framework on global expansion, this study utilizes a rather small number of data and, therefore, requires readers' discretion when interpreting the results of statistical analyses.

Practical implications

With the dynamic diversification‐coordination model, managers can recognize the level and characteristics of their firms' global expansion, not only at the firm level but also at the functional level. This allows managers to establish a global strategy tailored to each function, thus reconciling possible conflicts generated from different interests among different functions in the firm.

Originality/value

First, this article introduces a new perspective of analyzing the global expansion of firms by shifting the level of analysis from the firm level to the functional level where the new framework can reconcile the constant debates on globalization. Second, this article suggests an intuitive and theory‐based index measuring the degree of global expansion of firms.

Details

Management Decision, vol. 46 no. 1
Type: Research Article
ISSN: 0025-1747

Keywords

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